The present invention relates to a rope elevator which has a car and a counterweight which hang on suspension ropes and move in opposite directions along guiderails in an elevator hoistway, the car guide-plane formed by two car guiderails running parallel to the car-front and approximately through the center-of-gravity of the car, the elevator being driven by a drive unit with traction sheave which is so placed in the hoistway overhead above the travel-path of the counterweight that the upper part of the car can reach a position in the hoistway above this drive unit, and the suspension ropes running down from a hitch-point situated in the hoistway overhead in the vicinity of the counterweight-side side-wall of the hoistway and around one or two pulleys of the counterweight, then up and around the traction sheave of the drive unit, then down again and horizontally/diagonally across under two pulleys underneath the car, and finally up again to a second hitch-point on the car-side side-wall of the hoistway.
From DE 197 12 646 Al a machine-room-less rope elevator is known whose drive unit with traction sheave is arranged on a concrete plinth projecting into the elevator hoistway. However, this solution has certain disadvantages. The elevator hoistway and/or the landing floor have to be designed with strength in the vicinity of the proposed concrete plinth for the maximum stresses arising on the drive unit due to operation of the elevator. The necessary construction by builders of such a concrete plinth in an otherwise simple, cubical space causes considerable extra outlay. If the plinth is not executed as drawn, problems and delays in the installation of the elevator can occur.
FR 2 773 363-A3 discloses the machine-room-less arrangement of an elevator drive unit. This is mounted on a support which is fastened at one end to two counterweight guiderails and a car guiderail and at the other end via a console to a wall of the normally concreted elevator hoistway. Such a solution has significant disadvantages. The hoistway wall has to absorb an undefined proportion of the vertical forces acting on the drive unit. Furthermore, strain occurs in the support fastened to the hoistway wall and guiderails as a result of building shrinkage of the (concrete) hoistway wall and as a result of differing thermal expansion of the guiderails and hoistway wall (because of these problems the guiderails are fastened to the hoistway walls in longitudinally movable manner).
The task of the present invention is to propose a solution by means of which the advantageous arrangement of the drive unit can be realized while avoiding the disadvantages stated.
This task is solved according to the invention by the distinguishing characteristics of Patent claim 1. With the proposed fastening of the supporting construction of the drive unit on three guiderails, the operating forces acting on the drive, and the force of its weight, are essentially transmitted via these guiderails directly into the foundation of the elevator hoistway, which allows the required strength of the hoistway wall to be substantially reduced.
Advantageous embodiments and further developments of the invention are stated in the subclaims.
According to a preferred embodiment of the invention, placing the drive unit with its traction sheave, and usually also with the counterweight pulley(s), diagonally results in the center-of-gravity of the counterweight, which is located below the center of the counterweight pulley(s), coming to lie closer to the hoistway wall than is possible with an arrangement of the traction sheave and pulley(s) parallel to the counterweight, because of the distance of the traction sheave from the hoistway wall given by the dimensions of the drive unit. The space-saving arrangement of the counterweight achieved in this manner allows the use of a car with greatest-possible width.
A further preferred embodiment of the invention is achieved by the section of suspension rope running vertically from the traction sheave to the first car pulley being arranged in the free area of the hoistway between hoistway wall and car side-wall, which is not occupied by the travel-path of the counterweight and the guiderail fastening brackets surrounding it. Different from the arrangement of suspension ropes given as state of the art, where the stated section of suspension rope is guided between the guiderail fastening brackets surrounding the counterweight and the car side-wall, the preferred suspension rope arrangement proposed here causes no loss of installation space for the car. This is especially advantageous if, in the case of large building heights, substantial vibrations of the stated section of suspension rope are to be expected, and therefore relatively large free spaces needed around it.
Included in the advantageous embodiments of the invention is also that the first hitch-point of the suspension ropes is provided on the supporting construction of the drive unit. This saves time and costs for mounting a hitch-point support on the hoistway wall during installation of the elevator, and avoids a possible source of error.
In a further preferred embodiment of the rope elevator according to the invention, the drive unit is executed as a worm gear, the drive motor being arranged vertically in order to reduce the space required.
Also included in the preferred embodiments is that the counterweight is arranged at the side of, and adjacent to, the car, and with its guide-plane formed of two counterweight guiderails parallel to the side-wall of the car. Firstly, by this means an optimal utilization of the hoistway space is achieved, because free space at the side of the car is required for the opened access doors. Secondly, the drive unit can, if necessary, be made observable and accessible by means of inspection windows and/or service doors in the usually freely-available front of the hoistway.